The magnitude and source of air emissions from asphalt blowing operations

The US EPA has developed emission factors for estimating the emissions of filterable particulate, total organic compounds, and carbon monoxide from asphalt blowing operation sThese are published by the EPA in a series called AP-42, which contain factors for many manufacturing processes. The emission factors for asphalt blowing are acknowledged by the EPA to be of poor quality .Owens Corning has taken extensive data in various manufacturing facilities and an asphalt Pilot Plant to provide more information on air emissions from these operations . The results of that work clearly show that the current AP42 emission factors for asphalt processed by air blowing are deficient in that they omit significant emissions of SO x and HCl, overestimate particulate and CO emissions, and potentially underestimate both VOC and NO x emissions. In fact, SOx, which is not addressed by AP-42 ,is the major air emission contributed by the fumes from the asphalt blowing process when those fumes are incinerated .The sources of SO x from air blowing are discussed in detail in this paper .The impact of incineration temperature on carbon monoxide is also illustrated .With the exception of HCl, the hazardous air pollutants encountered in the asphalt blowing process are minimal.